A device that is described in, for example, JP 2013-100021A (Reference 1) is known as a seat reclining device for maintaining a seat back at a predetermined angle with respect to a seat cushion of a seat.
The seat reclining device is provided with a first bracket that is mounted on the seat cushion, a cam that rotates with respect to the first bracket, a pawl that is moved in a radial direction of the first bracket by the rotation of the cam, and a second bracket that is mounted on the seat back and rotates with respect to the first bracket. The pawl is moved outwardly by the rotation of the cam and external teeth of the pawl are engaged with internal teeth that are disposed on an outer circumferential wall of the second bracket so that the rotation of the second bracket is blocked. In this manner, the second bracket is maintained at a predetermined angle with respect to the first bracket.
In addition, the cam is biased, by a spiral spring, in a predetermined direction of rotation so that the engagement between the external teeth of the pawl and the internal teeth of the second bracket is maintained. The spiral spring is, for example, accommodated in an accommodating portion that is disposed in the first bracket.
In Reference 1, the accommodating portion is open to an outer side. Accordingly, dust or the like may infiltrate into the accommodating portion. Regarding this point, techniques for covering the spiral spring by using a cover have been known (refer to JP 2013-215269A (Reference 2)).
In the case of Reference 2, however, the cover is mounted outside the first bracket, and thus it is difficult to mount the first bracket on a fixing member (for example, a frame that constitutes the seat cushion).